Growth kinetics and siderophore production of S. epidermidis (planktonic growth) in fRPMI and fRPMI-Fe1. Bacteria were overnight pre-incubated in fRPMI and incubated in fRPMI or in fRPMI-Fe1. The right y-axis, the dotted line with empty diamonds (fRPMI-Fe1) and the dotted line with empty squares (fRPMI) represent siderophore activity, measured at 630 nm. The left y-axis, the full line with filled triangles (fRPMI-Fe1) and the full line with crosses (fRPMI) represent the growth curve, given as OD600. The x-axis contains the time in hours. The line that links the data points helps to clarify the results at each time point measured. The error bars represent standard deviations. At each time point 15 samples from three independent cultures (five samples from each culture) were assessed.